In addition to Lafora's Progressive Myoclonic Epilepsy, there are numerous single-gene defect diseases that have devastating effects on the children of adult carriers (e.g. Rett's syndrome, fragile x syndrome, Canavan's disease, and Tay-Sachs disease). For all of these diseases, there are support groups formed by parents and friends of afflicted children. In all cases, the mutated gene is known and cloned. But copies of the potentially life-saving genes sit dormant in research laboratories because of problems in expressing an exogenous gene throughout the brain. Due to the difficulties in delivering large molecule therapeutics across the brain capillaries, there is a perception that the blood-brain barrier (BBB) may be an insoluble problem. Heroic measures, such the transient disruption of the BBB with osmotic shock, have yet to be evaluated for delivery of gene therapeutics in clinical trials. Alternative methods are also not without problems; within the current year the NIH placed a halt on all trials where viral vectors were being used to deliver gene therapies. This action suggests a need to develop and test non-viral alternatives for the delivery of (large-molecule) genes across the BBB. We will test the hypothesis that recently developed immunoliposome BBB delivery systems can be used to successfully promote a gene therapeutic through the BBB of knock-out mice with Lafora's Progressive Myoclonic Epilepsy (PME), after intravenous administration. We propose that if this non-viral delivery system can treat the disease in animal models, an immunoliposome-based cure for this fatal epilepsy can be developed for clinical use. The aims are: (1) To prepare pegylated immunoliposomes (PIL) for delivery of the normal EPM2a/laforin gene; (2) to administer PILs in a knockout mouse model of Lafora's Disease; (3) to confirm uniform delivery of the gene to the brain after intravenous injection, with amelioration of the progressive disease; and (4) to develop an optimal therapeutic regimen which arrests the fatal onset of Lafora's disease in the knock-out mice.